In so-called jump-lifts, the elevator hoistway is taken into use already before the full length of the elevator hoistway has been completed. The top part of the elevator hoistway is constructed at the same time as an elevator car moving in the already completed bottom part of the elevator hoistway serves people on the lower floors of the building. In jump-lifts, the elevator car moving in the bottom part of the elevator hoistway is supported and moved during the construction-time use suspended on hoisting ropes that are supported by a supporting platform in the elevator hoistway, which ropes are moved with a hoisting machine that is usually supported on the supporting platform. Installation work is done in the parts of the elevator hoistway above this supporting platform.
Generally in jump lifts the elevator car moving in the lower parts of the elevator hoistway is supported by a movable supporting platform positioned above the car in the hoistway. Often the car is moved during construction-time use with a hoisting machine supported on this supporting platform, but alternative locations for the hoisting machine also exist. The installation work in the parts of the elevator hoistway above this supporting platform is performed from a movable platform or corresponding in the elevator hoistway, which installation work comprises, among other things, the installation of guide rails and electrification in the elevator hoistway. When the elevator hoistway under construction above the supporting platform has reached a sufficient stage of completion, the completed part of the elevator hoistway can be taken into use. In this case a jump lift is performed, where the supporting platform is raised and mounted to a higher position in the elevator hoistway.
A travelling cable is fixed to the car of a passenger transport elevator and/or freight transport elevator, via which travelling cable the elevator car is in connection with the elevator control center. The travelling cable is typically a flat cable and comprises electrical conductors and a load-carrying bearer surrounded by a protective envelope. The travelling cable is used for power transmission and with it the necessary electrical energy is supplied to the elevator car and with it data is transmitted between the signaling devices of the elevator car, such as car call pushbuttons, communication devices and displays, and also the control system of the elevator. The load-bearing part of the travelling cable is frequently a steel rope bearer, typically a 6-strand or 8-strand steel rope, which comprises a steel core and strands passing around it. The travelling cable is typically fixed at the first end of the rope bearer to the elevator car and at the second end to the elevator hoistway by a travelling cable clamp.
Elevator safety codes require that travelling cables are supported by their integral steel ropes. In prior art, this is accomplished by stripping back the insulation and securing the ropes using proprietary clamps. A problem with known travelling cable clamp solutions with jump lifts has been that the travelling cable is ruined and unsafe to use. Especially in jump lifts, the travelling cable must be extended each time the supporting platform and the machine room are raised without cutting open the insulation.